Deep Trench Capacitor Sidewalls for Higher Capacitance Density
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Solution Overview
Problem
Existing semiconductor devices face challenges in reducing semiconductor device sizes while maintaining or increasing capacitance, as increasing lateral size of capacitor structures contradicts semiconductor design principles aimed at reduced power consumption and smaller form factors.
Innovation Solution
Implementing a deep trench capacitor structure with non-uniform top view widths and zig-zag sidewalls to increase the surface area of electrode layers, allowing capacitance to be increased vertically without significantly expanding the lateral footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lateral size of capacitor structures is increased to maintain or increase capacitance, then capacitance is improved, but device size increases which contradicts semiconductor design principles for reduced power consumption and smaller form factors
Solution Approach 1:
The patent transitions from planar capacitor structures to three-dimensional trench capacitor structures. By etching deep trenches into the substrate and forming electrodes along the trench walls and bottom, the capacitor utilizes the vertical dimension (depth) to increase capacitance. This dimensional change allows capacitance to scale without proportionally increasing the lateral footprint, directly resolving the contradiction between maintaining capacitance and reducing device size.
Solution Approach 2:
The trench capacitor structure nests multiple functional layers within a confined vertical space. The structure includes a bottom electrode layer, dielectric layer, and top electrode layer nested sequentially within the trench depth. This nesting approach packs maximum capacitance-generating interfaces into a small lateral area by exploiting vertical stacking, thereby increasing capacitance without expanding the device's horizontal dimensions.
2Reliability
If deep trench structures are formed to increase capacitance vertically, then capacitance is improved, but manufacturing complexity increases
Solution Approach 1:
The formation of the trench capacitor structure is segmented into distinct process stages: trench etching, bottom electrode formation, dielectric layer deposition, and top electrode formation. Each stage uses specialized processing techniques optimized for that specific step. This segmentation allows complex three-dimensional structures to be built through a sequence of manageable, well-controlled manufacturing steps, reducing overall process complexity despite the vertical complexity of the final structure.
Solution Approach 2:
The trench structure is pre-formed through deep etching operations before any electrode or dielectric layers are deposited. This preliminary action creates the three-dimensional scaffold that guides subsequent material deposition. By establishing the vertical geometry first, subsequent layers can be conformally deposited using standard thin-film techniques, avoiding the need for complex simultaneous multi-layer patterning processes.
Data Source
AI summary
A trench for a trench capacitor structure is formed to have a non-uniform top view width along the length of the trench. The non-uniform top view width results in the sidewalls of the trench having a zig-zag arrangement, a semi-circular or curved arrangement, or another non-straight-lined arrangement along the length of the trench. This provides a greater amount of surface area along the sidewalls for the electrode layers and insulator layer of the trench capacitor structure, thereby increasing the capacitance of the trench capacitor structure.